A systematic assessment of Morchella using RFLP analysis of the 28S ribosomal RNA gene

Abstract

Morels (Morchella spp.) are one of the most highly prized edible mushrooms found in the wild of North America. Because environmental conditions can cause members of the genus to vary morphologically, the number of species has been disputed. Some authors classify the genus into three to five species, while others argue for as many as 50 species. DNA from lines of Morchella and a closely related genus (Verpa) was isolated. The large subunit of the ribosomal DNA repeat was amplified using the polymerase chain reaction and then digested with restriction enzymes. Restriction fragment length polymorphisms were found among the lines investigated and used to separate the lines into genotypic classes. More genetic variation may occur between geographically isolated populations of the same species than between two putatively distinct species. The phylogenetic tree developed from restriction data suggests that the black morels (M. angusticeps, M. elata, and M. conica) and the yellow morels (M. esculenta, M. crassipes, and M. deliciosa) are separate taxonomic groups.

Key Words:

• Morchella
• morels
• phylogeny
• RFLPs
• ribosomal DNA